Metal working – Means to assemble or disassemble – With work-holder for assembly
Reexamination Certificate
2000-07-13
2003-02-18
Vidovich, Gregory M. (Department: 3726)
Metal working
Means to assemble or disassemble
With work-holder for assembly
C029S721000, C144S058000, C269S041000
Reexamination Certificate
active
06519825
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a machine for joining two members at a miter joint, a clamping head assembly for use in such a machine, and a method of retrofitting an existing joining machine to include the present clamping head assembly. More particularly, the preferred embodiment of the present invention relates to a frame making machine used for joining two frame members at a miter joint, where the machine includes a clamping head assembly with two fence members, at least one of which is movable, which are used to align the frame members in the proper orientation. The present invention also relates to such a clamping head assembly, as well as to retrofitting a machine that includes a conventional head assembly with the present head assembly. It should be noted that although the preferred embodiments of the present invention will be shown and described as being intended for use in the frame making industry, uses of the present invention in other industries that require members to be joined together at a miter joint are also contemplated as being within the scope of the invention, for example the woodworking industry.
A miter joint is a corner joint formed by fitting two members together at their respective edges, wherein each edge is cut at some angle; the line defined at the joint between the adjacent edges is the miter angle. Conventionally, for adjacent edges cut at the same angle, if the included angle between the two members is 90 degrees, the miter angle will be 45 degrees, and if the included angle is 60 degrees, the miter angle will be 30 degrees. Therefore, a miter angle by definition is an oblique angle.
Machines for joining two frame members at a miter joint are known in the art. One popular machine, which is shown in an exploded view in
FIG. 1
, is the “Mitre-Mite VN 4 Electronic,” which is manufactured and distributed by Alfamachine-ITW/AMP of Vernon Hills, Ill. The frame making machine
10
includes a work table
12
with a preferably horizontal work surface
14
. Briefly, as known to those of ordinary skill in the art, the machine
10
operates as follows. First, one frame member is aligned along each one of the two fence members (
22
,
24
) with a miter joint therebetween. Next, the frontal clamp
18
(optional) moves horizontally in a direction that is generally coincident with the miter joint, and pushes each of the two frame members against its respective fence member (
22
,
24
). Third, the vertical clamp (
20
) engages the frame members from the top, pushing them downwardly against the work surface
14
. Finally, the two frame members are nailed together at the miter joint by one or more nails (e.g., V-nails, corrugated fasteners or other fasteners) that are driven upwardly into the miter joint from a nail driving mechanism that is seated below the work surface
14
. After the nailing operation, the two frame members (which are now a single unit) can be removed from the machine since they have been joined together at the miter joint.
Since the present invention relates primarily to the methods and apparatuses used to clamp the frame members in place, these features of the prior art machine will be described next in more detail. The machine
10
includes three primary clamping subassemblies: (1) a stationary clamping assembly
16
; (2) a movable frontal clamp assembly
18
; and (3) a movable vertical clamp assembly
20
. It should be noted that since these features are known to those of ordinary skill in the art, only the major components of each subassembly will be described below.
The stationary clamping assembly consists primarily of two stationary fence members
22
and
24
that are relatively rigidly affixed to the work surface
14
by a plurality of screws
26
extending through a plurality of associated holes
28
. The holes
28
are in the form of elongated slots to allow for some adjustment of the positioning of the stationary fence members
22
,
24
. Knobs
30
are useful for adjusting the vertical angle of the edge of the fence members to better accommodate and achieve a tight fit between frame members having angled or non-uniform edges. A shown in the
FIG. 1
view, the inner (or left) side of each of the stationary fence members defines a positioning edge upon which a respective edge of one of the frame members intended to be joined together is seated against.
The second subassembly, the movable frontal clamp assembly
18
, includes a movable frontal clamp member
32
, which is configured to move within track
34
. The position of the frontal clamp member
32
may be varied by moving the securing knob
36
to another one of the holes
38
. In operation, the movable front clamp member
32
is moved from a first position in which it is drawn backward (toward the left-hand side of
FIG. 1
) to a second position (toward the right-hand side of
FIG. 1
) in which it is clamping against the frame members intended to be joined together. The direction of travel of the frontal clamp member
32
is essentially coincident with the miter between the two frame members being joined together.
The third subassembly, the movable vertical clamp assembly
20
, includes a pressure plate
37
that is attached to a rod
39
. The rod
39
is attached to a support structure
40
, which is in turn connected to two cylinders
42
. The cylinders
42
are rigidly affixed to the work surface
14
from below so that the attachment plates
44
are below the work surface
14
and the cylinders
42
extend through holes
45
to be situated above the work surface. If necessary, the horizontal location of the pressure plate
37
may be adjusted by loosening handle
46
, and then sliding the threaded dowel
48
within the slot
50
. The vertical height of the pressure plate
37
may be adjusted by manipulating the other handle
52
. In operation, the cylinders
42
are withdrawn to push the pressure plate
37
downwardly upon the top of the frame members being joined together at the miter joint. In this manner, the frame members are firmly held down when the fastener(s) (e.g., V-nails, corrugated fasteners) are inserted from below.
One common problem with many frame assembly machines of the prior art, such as the one described above, is that the two frame members being joined together may not be properly held together at the miter joint. There may be a slight space between the two frame members at the miter joint prior to nailing. If this is the case, when the frame members are nailed together, there will be an unsightly gap between the two frame members at the joint. That is, the miter joint may be too wide along its entire length, resulting in a visible air space along the entire length of the miter joint, or the miter joint may be uneven, whereby a portion of the joint has a visible air space and another portion is tight with no visible air space. Neither of these two situations is desirable since the intent is to arrive at a tight miter joint with no visible gap between the two frame members.
Accordingly, one object of the present invention is to provide an improved frame assembly machine which is capable of consistently making a tight miter joint.
Another object of the present invention is to provide a clamping head assembly for use with a frame assembly machine whereby the resulting miter joints are tight.
A third object of the present invention is to provide a clamping head assembly for use with a frame machine where the assembly includes at least one movable fence member for properly positioning the frame member within the machine prior to the nailing operation.
A fourth object of the present invention is to provide a clamping head assembly that applies a force to the frame members being joined together at a miter joint, where that force is applied in a direction that is approximately perpendicular to the miter joint.
An additional object of the present invention is to provide a method of retrofitting an improved clamping head assembly upon an existing frame assembly machine.
These and other objects of the present invention a
Lambert Anthony
Stone James W.
Breh Donald J.
Croll Mark W.
Hong John C.
Illinois Tool Works Inc.
Soltis Lisa M.
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